Page 113 - Cardiac Electrophysiology | A Modeling and Imaging Approach

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Figure 4.1. Single cell in a volume conductor. ϕ ,ϕ are the intracellular and extracellular potentials,
°
i
respectively, immediately adjacent to the membrane surface S. σ ,σ are the intracellular and
i
°
extracellular conductivities. The transmembrane potential is V = ϕ – ϕ . The transmembrane
0
i
m
current is i .
m

Figure 4.2. Definition of a solid angle. The solid angle Ω at observation point P, subtended by the
surface S. The area intercepted on a unit sphere (defining Ω) is shown by the black surface.